Whether as a structural material or a functional material, polyimide has been listed as one of the most promising engineering plastics in the 21st century by various countries. Polyimide film processed by polyimide resin is particularly suitable for use as flexible printed circuit board substrate and various high-temperature electrical insulation materials, also known as "gold film" because of its excellent insulation and mechanical properties.
Polyimide film (hereinafter referred to as PIF) there are two main synthesis processes: one synthesis method is thermoimide method, which is suitable for the production of PIF below electronic grade; The other is chemical iminization, which is suitable for PIF production above electronic grade. Compared with the thermal imide process, the PIF product prepared by the chemical imide method has better performance and stronger market competitiveness. Dimethylformamide (DMF) is an important solvent for the preparation of high-end PIF by the chemical imide method, and the index requirements are more stringent, especially the moisture requirements are controlled within 100ppm. At present, 90% of domestic manufacturers are using the thermal imide production process, and foreign countries have basically completed the chemical imide method to replace the thermal imide method.
Polyimide film belongs to the high-tech barrier industry, at present, there are 40-50 polyimide film manufacturers of different sizes in China, and basically have achieved PIF self-sufficiency below the electronic level. However, about 85% of high-end polyimide films rely on imports. Its main market is divided among overseas companies such as DuPont, Toray, Jongyoun and Ube. There are only 3 factories in China using chemical imide production process, which started relatively late. However, with the flexible copper cladding (FCCL) market maintaining a high growth rate, as well as the rapid popularization of OLED demand for flexible films, the high-end electronic grade polyimide film market will be in a period of rapid expansion, but also stimulate the domestic PIF manufacturers technology replacement and expansion.
Electronic grade PIF is mainly used for flexible electronic substrates. With the development of The Times, high-end electronic products need light and thin substrates, and large information transmission and recording capacity. This requires that the printed circuit board (PCB) has good heat dissipation, can be bent, folded, wound, and can be moved and expanded at will in three-dimensional space, only flexible printed circuit boards are selected. The flexible printed circuit board (FCCL) is used to make copper clad plate (FCCL) by compounding copper poisons onto electronic polyimide films.
